A method is described for transmitting signals in a mobile communication system which splits an information block into a plurality of split-information blocks and performs a hybrid automatic repeat request (HARQ) process upon each of the split-information blocks. A method is also described for reducing control information overhead by transmitting control information only through one control channel when splitting an information block and transmitting split-information blocks through a plurality of subframes or a plurality of resource blocks. The segmentation of the information block is performed in a physical layer to reduce medium access control (MAC) overhead and to simplify implementation.